364 



NA TURE 



{Mar. 7,1872 



a practised mesmeriser, and was able to produce on my own 

 patients almost the whole range of phenomena which are exhi- 

 bited in public as illustrative of ** mesmerism " or "electro- 

 biology." I carried on numerous experiments in private, and 

 paid especial atteni ion to the conditions under which the phe- 

 nomena occur. During the last seven years I have had repeated 

 opportunities of examining the phenomena that occur in the 

 presence of so-called " mediums." often under such favourable 

 conditions as to render trick or imposture simply impossible. I 

 believe, therefore, I may lay claim to some qualifications for 

 comparing the mesmeric with the mediumistic phenomena with 

 especial reference to Mr. Tylor's suggestion, and I find that there 

 are two great characteristics that broadly distinguish the one from 

 the other. 



1. The mesmerised patient never has dnnhts of the reality of 

 what he sees or hears. He is like a dreamer to whom the most 

 incongruous circumstances suggest no idea of incongruity, and lie 

 never inquires if what he thinks he perceives harmonises with liis 

 actual surroundings. He has, moreover, lost his memory of 

 what and where he was a few moments before, and can give no 

 account, for instance, of how he has managed to get out of a 

 lecture-room in London to which he came as a spectator half an 

 hour before, on to an Atlantic steamer in a hurricane, or into 

 the recesses of a tropical forest. 



The assistants at the seances of Mr. Home or Mrs. Guppy are 

 not in this state, as I can personally testify, and as the almost 

 invariable suspicion with which the phenomena are at first re- 

 garded clearly demonstrates. They do not lose memory of the 

 immediately preceding events ; they criticise, they examine, they 

 take notes, they suggest tests — none of which the mesmerised 

 patient ever does. 



2. The mesmeriser has the power of acting on " certain sensi- 

 tive individuals" (not on "assemblies" nf people, as Mr. Tylor 

 suggests), and all experience shows that those who are thus 

 sensitive to any one operator are but a small proportion of the 

 population, and these almost always require previous manipula- 

 tion with passive submission to the operator. The number who can 

 be acted upon without such previous manipulation is very small, 

 probably much less than one per cent. But there is no such 

 limitation to the number of persons who simultaneously see the 

 mediumistic phenomena. The visitors to Mr. Home or Mrs. 

 Guppy all see whatever occurs of a physical nature, as the records 

 of hundreds of sittings demonstrate. 



The two classes of phenomena, therefore, differ fundamen- 

 tally ; and it is a most convincing proof of Mr. Tylor's very 

 slender acquaintance with either of them, that he should even 

 suggest their identity. Tlie real connection between them is 

 quite in an opposite direction. It is the mediums, not the assis- 

 tants, who are "sensitives." They are almost always subject 

 to the mesmeric influence, and they often exhibit all the charac- 

 teristic phenomena of coma, trance, rigidity, and abnormal sense- 

 power. Conversely, the most sensitive mesmeric patients are 

 almost invariably mediums. The idea that it is necessary for me 

 to inform " spiritualists" that I believe in the pov^'er of mesmerisers 

 to make their patient believe what they please, and that this "in- 

 formation" might "bring about investigations leading to val li- 

 able results," is really amusing, considering that such investiga- 

 tions took place twenty years ago, and led to this important 

 result — that almost all the most experienced mesmeris's (Prof 

 Gregory, Dr. Elliotson, Dr. Reichenbach, and many others) be- 

 came spiritualists ! If Mr. Tylor's suggestion had any value, 

 these are the very men who ought to have demonstrated the sub- 

 jective nature of mediumistic phenomena ; but, on the contrary, 

 as soon as they had the opportunity of personally investigating 

 them, they all of them saw and admitted their objective reality. 

 Alfred R. Wallace 



Development of Barometic Depressions 



Ik I have misrepresented Mr. Dey's views, the misrepresenta- 

 tion was certainly unintentional ; but after fairly considering his 

 letter in Nature of February 29, I am unable to see that I have 

 misrepresented liis views, so far as they are exposed in his " Laws 

 of the Winds prevailing in Western Europe." Part II., of 

 course, I ignored. It is not yet published ; for aught I know, is 

 not yet written ; and as I have not the pleasure of a personal 

 acquaintance with Mr. Ley, it is difficult to understand how I 

 could be expected to express any opinion on a book which is 

 still in the womb of the future. But as to the present work. 



Part I., which I read and reviewed, it is mainly occupied with 

 instances, ingeniously worked out, in illustration of the rule 

 which he distinctly enunciates, that revolving storms are due to 

 the depression of the barometer caused by a heavy rain over a 

 large area. Perhaps, in the same way, Part II. is to be mainly 

 occupied by an examination and discussion of the still more 

 numerous instances in which revolving storms have not followed 

 heavy rain over a large area ; and if so, I shall be glad in due 

 time to give it my be^t attention. But for the present, having 

 before me merely the author's existing work, I repeat what I 

 have, in effect, already said, that the occasional or even frequent 

 sequence of rain and storm does not establish between the two a 

 relationship of cause and effect. 



A very casual examination of our own registers, and those of 

 Western Europe generally, would show that instances of rainfall 

 quite as great as any that Mr. Ley adduces, happen very fre- 

 quently without any storm following ; and clearly if Mr. Ley's 

 rule is sound, it must apply to all instances which cannot be 

 claimed as exceptions, and that not only in our own latitudes, 

 but in other parts of the woild, and especially in those parts 

 where the rainliill is excessive. It was certainly not " necessary " 

 to travel to Khasia for instances of the failure of this rule ; but 

 its failure was exhibited in the nio>t full and clear manner by a 

 reference to that extraordinary rainfall. 



Mr. Ley speaks of some "fact" relative to the Himalayas 

 which "may be denied." I do not quite understand what fact 

 he means. The facts I have spo'xen of are the " heavy and 

 long continued precipitation," and a very great depression 

 of the barometer." If it is either of these that he wishes to 

 deny, I can only say that his doing so confirms my former state- 

 ment that he has confined his investigations too exclusively to 

 Western Europe. But when I spoke of the one as causing the 

 other, it was not as stating a fact, but as suggesting a probability ; 

 whilst whether there is or is not " a region in which Ballot's 

 rules are contravened " I am unable to say ; if there is I have 

 not discovL-red ir, and I don't know where it is, but it is not near 

 the Himalayas, where, so far as we know, the circuit of the wind 

 is quite in accordance with Buys Ballot's Law, though on a scale 

 of extreme m.agiritude — of such magnitude indeed that our 

 observations do not extend to the end of it. It is curious that 

 an author who, like Mr. Ley, writes sensibly within his professed 

 boundaries, should have limited his studies so closely as he appears 

 to have done ; but as the remark to which I have just referred 

 shows pretty conclusively that he has not examined into the range 

 of the barometer in India, so the remark which he makes about 

 the advance of cyclones " in the West Indies, e.g.," shows that 

 he is strangely in the dark as to the variations of temperature in 

 the tropical Atlantic. 



The columns of Nature are not the place to discuss at length 

 such well-worn subiects as either Buys Ballot's law or the in- 

 fluence of the earth's rotation, and certainly whether the earth's 

 rotation does or does not produce the effect attributed to it, was 

 quite beyond the scope of my former allusion to it ; but I said 

 and repeat that its influence is not " obvious," that an argument 

 based on it is not a " truism," and that to apply these words to 

 a point that is at any rate doubtful is both objectionable and im- 

 proper. J. K. L. 



Solar Intensity 



I have read with interest the criticism in your last number of 

 Padre Secchi's Solar Intensity Apparatus. With reference to 

 the single point of the discordant results obtained by thermo- 

 meters with bulbs of dilTerent size, I would observe that I en- 

 countered a similar difficulty some years ago in investigating the 

 adaptability of the instrument invented by Herschel, commonly 

 called the " black bulb in -t'nciio," to regular comparable meteo- 

 rological observations. I found that the large bulbs always gave a 

 higher reading than the small bulbs. I supposed this to proceed 

 from the colder stem depriving the blackened bulb of its heat, 

 the larger bulb, of course, losing less than the smaller, and I 

 overcame the difficulty entirely by having about an inch of the 

 stem as well as the bulb coated with lamp-black. I am not 

 sure, however, that this would answer so well in a non-exhausted 

 chamber. Probably a small bulb will always be cooled by con- 

 vection more rapidly than a large one. 



In the excess of the temperature indicated by the improved 

 instruments I have referred to over the temperature of the air, at 

 the same height — usually 4!!. — above the soil (which is also very 



